Georgia-based guitarist, singer, and songwriter Beverly "Guitar" Watkins is one part soul singer, one part rockin' roadhouse mama, and one part gifted songwriter. She's also been chronically under-recorded for a woman with her résumé: she spent the early '60s playing rhythm guitar with Piano Red & the Interns. She recorded with Piano Red from 1959 until the mid-'60s, and can be heard on his popular singles "Doctor Feelgood" and "Right String But the Wrong Yo Yo." Watkins learned guitar and got her earliest musical sensibilities from several of her aunts, who had a quartet name...